152 MOLLUSCA. 



No. 743. Orthis oblata, Hall. 



... '...:'...' :■• 



H^HgBi Tliis specimen is from the Lower Helderberg (Up- 

 ;' ,. |» per Silurian), Albany Co., N. Y. Price, $0.20. 



mm' 



No. 744. Orthis lynx, Eicnwald. 



Two specimens, young and adult. From the Hudson River group, Ohio. 



Price, $0.40. 

 No. 745. Orthis musculosa, Hall. 



Interior cast. From the Oriskany sandstone, Albany Co., N. Y. 



Price, $0.25. 



No. 746. Orthis occidentalis, Hall. 



From the Hudson River group (Lower Silurian), Savannah, 111. Shows finely 

 the areas and deltidium. Price, $0.25. 



No. 747. Orthis subcarinata, Hall. 



From the Lower Helderberg (Upper Silurian), Albany Co., N.Y. Price, $0.15. 



No. 748. Streptorhynchus hipparionyx, Vanux. 



Interior of Valve. From the Oriskany sandstone (Devonian), Albany Co., 

 N. Y. Price, $0.40. 



No. 749. Streptorhynchus (Orthis) umbraculum, Buch. 



Two specimens, on pedestal. From the Sub-carboniferous, Grerolstein, Rhe n- 

 ish Prussia, and now in the private Geological Cabinet of Mr. Ward, Rochester. 



Price, $0.50. 



No. 750. Strophodonta magninca, Hall. 



From the Oriskany sandstone (Devonian), Albany Co., N.Y. Price, $0.35. 



No. 751. Strophodonta vascularis, Hall. 



From the same locality as the preceding. Price, $0.35. 



No. 752. Productus pyxidiformis, Koninck. 



The Productidae, to which this and the next three Brach- 

 iopods belong, are concavo-convex shells, with straight hinge- 

 bine, large beak, and no arm supports. From the Carbonifer- 

 ous limestone, Derbyshire, England, and now in the Ward 

 Museum, University of Rochester. Price, $0.60. 



No. 753. Productus costatus, Sow. 



From the Coal Measures, Iowa. Price, $0.20. 



No. 754. Productus Wilberianus, McChesney. 



This specimen is from the Carboniferous limestone, Missouri. Price, $0.25. 



